In an important experiment, a radioactively labeled bacteriophage was allowed to infect bacteria. in a first trial, the phage contained radioactive dna, and radioactivity was detected inside the bacteria. next, phage containing radioactive protein was used, and the radioactivity was not detected inside the bacteria. these experiments led to the conclusion that

The correct answer will be- DNA acts as the genetic material of the phage

Explanation:

A bacteriophage is a virus which infects the bacteria by inserting its genetic material into the host cell and using its DNA replication machinery to replicate or divide.

In the given question, when DNA was radiolabeled, radioactive DNA was observed in the host cell but when the protein was radiolabeled, it was not observed in the host cell as the molecule to be inserted in the host cell is the DNA (genetic material) to be replicated.

Thus, DNA acts as the genetic material of the phage is the correct answer.